It's a good idea to fix this for all recipe downloads, since it's probably hapening for others as well. I would suggest making this change in the process_images method in the web.fetch.simple module. The best way to do it would be to read in the image using QImage and write it out as jpeg after checking that the image is valid. If invalid, then dont write the image. Go ahead and submit a patch or open a ticket and I'll fix it when I get some time.